Evaluation of a Box Method-Based Total Pressure Boundary Condition for the Square Plaque Diffuser
|Forfattere||Mikhail Koupriyanov, Brad Tully & Julian Rimmer|
|Institusjon||E.H. Price Ltd.|
|Redaktør||Vojislav Novakovic, Sten Olaf Hanssen, Hans Martin Mathisen|
AbstraktComputational Fluid Dynamics (CFD) is quickly becoming a widely used analysis tool in the design of occupied spaces. The accuracy of the simulation depends largely on the accuracy of the method used to model the diffuser. This study builds upon the work previously published by the authors. Two box method type boundary conditions with either a total pressure definition or a constant velocity are used to model a common square plaque diffuser. These boundary conditions are thoroughly evaluated by studying the behavior of the jet created by the diffuser that is placed close to a wall. Comparisons are made to experimental data as well as to CFD results that use a full geometric model of the diffuser. In general, the development of the jet is under predicted by the CFD results and the temperature profiles are not predicted as accurately as the velocity profiles. The accuracy of the box method tends to degrade as the diffuser is moved closer to the wall and as the flow rate is increased. The results also show no clear advantage in using a total pressure over a constant velocity since the predictions of both are nearly identical.
ReferanserBin Y., Sekhar S. C. \"Three-Dimensional Numerical Simulation of a Hybrid fresh Air and Recirculated Air Diffuser for Decoupled Ventilation Strategy.\" Building and Environment Vol. 42(5), pp. 1975-1982, 2007.
Cao G., Sivukari M., Kurtnitski J., Ruponen M., Seppänen O. \"Particle Image Velocimetry (PIV) Application in the Measurement of Indoor Air Distribution by an Active Chilled Beam.\" Building and Environment Vol. 45(9), pp. 1932-1940, 2010.
Cao G., Kurtinski J., Ruponen M., Seppänen O. \"Experimental Investigation and Modeling of the Attached Plane Jet Velocity Characteristics in the Transition Process in a Room.\" HVAC&R Research Vol. 15(3), pp. 489-508, 2009.
Cehlin and M., Moshfegh B. \"Numerical Modeling of a Complex Diffuser in a Room with Displacement Ventilation.\" Building and Environment Vol. 45(10), pp. 2240-2252, 2010.
Chen Q., Srebric J. \"Simplified Diffuser Boundary Conditions for Numerical Room Airflow Models.\" ASHRAE RP-1009, 2001.
Chen Q., Moser A. \"Simulation of a multiple-nozzle diffuser.\" Proceedings of the 12th AIVC Conference, Vol. 2, pp. 1-14, 1991.
Djunaedy E., Cheong K. W. D. \"Development of a Simplified Technique of Modeling Four-Way Ceiling Air Supply Diffuser.\" Building and Environment Vol. 37(4), pp. 393-403, 2002.
Einberg G., Hagström K., Mustakallio P., Koskela H., Holmberg S. \"CFD Modeling of an Industrial Air Diffuser - Predicting Velocity and temperature in the Near Zone.\" Building and Environment Vol. 40(5), pp. 601-615, 2005.
Fontaine J.R., Rapp P., Koskela H., Niemelä R. \"Evaluation of Air Diffuser Flow modeling Methods, Experiments and Computational Fluid Dynamics Simulations.\"Building and Environment vol. 40(3), pp. 377-389, 2005.
Fox R.W., McDonald A.T. \"Introduction to Fluid Mechanics, 5th Edition.\" John Wiley & Sons, 1998.
Hu S.C. \"Airflow Characteristics in the Outlet Region of a Vortex Room Air Diffuser.\" Building and Environment Vol. 38(4), pp. 553-561, 2003.
Huo Y., Haghighat F., Zhang J. S., Shaw C. Y. \"A Systematic Approach to Describe the Air Terminal Device in CFD Simulation for Room Air Distribution Analysis.\" Building and Environment Vol. 35(6), pp. 563-576, 2000.
Koskela H. \"Momentum Source Model for CFD Simulations of Nozzle Duct Air Diffuser.\" Building and Environment Vol. 36(10), pp. 1011-1020, 2004.
Luo S., Heikkinen J., Roux B. \"Simulation of Air Flow in the IEA Annex 20 test Room - Validation of a Simplified Model for the Diffuser in Isothermal Test Cases Nozzle.\" Building and Environment Vol. 39(12), pp. 1403-1415, 2004.
Luo S., Roux B. \"Modeling of the HESCO Nozzle Diffuser Used in IEA Annex-20 Experiment Test Room.\" Building and Environment Vol. 39(4), pp. 367-384, 2004.
Menter F., Egorov Y. \"Turbulence Modeling of Aerodynamic Flows.\" Proceedings of the International Aerospace CFD Conference, 2007.
Nielsen P. V. \"Flow in Air Conditioned Rooms.\" Ph.D. Thesis (English Translation), Danfoss A/S, Denmark, 1974.
Nielsen P. V. \"Description of Supply Openings in Numerical Models for Room Air Distribution.\" ASHRAE Transactions Vol. 98, Part 1, 1992.
Samir R., Traboulsi, Hammoud A., Farid M. \"Effects of jet Inclination Angle and Geometrical Parameters on Air Curtain Performance.\" ASHRAE Transactions Vol. 115, Part 2, 2009.
Schälin A., Nielsen P. V. \"Impact of Turbulence Anisotropy Near Walls in Room Air Flow.\" Indoor Air Vol. 14(3), pp. 159-168, 2004.
Skovgaard M., Nielsen P. V. \"Modeling Complex Inlet Geometries in CFD - Applied to Air Flows in Ventilated Rooms.\" 12th AIVC Conference, Ottawa, Canada, 1991.
Sun Y., Smith T.F. \"Air Flow Characteristics of a Room with Square Cone Diffusers.\" Building and Environment Vol. 40(5), pp. 589-600, 2005.
Tutu N. K., Krishna C. R., Thomas A. \"Characterization of Airflows at the Exit of Registers Using Laser Doppler Velocimetry (LDV).\" ASHRAE Transactions Vol. 110, pp. 709-721, 2004.
Wang M., Chen Q. \"Assessment of Various Turbulence Models for Transitional Flows in Enclosed Environment.\" HVAC&R Research RP-1271, 2009.
Yu H., Liao C. M., Liang H. M., Chiang K. C. \"Scale Model Study of Airflow Performance in a Ceiling Slot-Ventilated Enclosure: Non-Isothermal Condition.\" Building and Environment Vol. 42(3), pp. 1142-1150. 2007.
Zhang, T., Lee, K.S., and Chen, Q. 2009. “A Simplified Approach to Describe Complex Diffusers in Displacement Ventilation for CFD Simulations.” Indoor Air, 19(3), 255-267.
Forrige artikkel Neste artikkel